Apparatus for lapping dies



April 30, 1957 Filed May 27, 1955 G- P. HAFER APPARATUS FOR LAPPING DIES 3 Sheets-Sheet 1 m/ys/vrofi G. I? HAFER Err-MW? ATTORNEY April 30, 1957 G. P. HAFER 2,790,273

APPARATUS FOR LAPPING DIES :5 Shets-Sheet 2 Filed May 27, 1955 FIG . INVA'NTOR G P HA! I? A rink/v5) April 30, 1957 G. P. HAFER 2,790,273

APPARATUS FOR LAPPING DIES Filed May 27, 1955 3 Sheets-Sheet 3 INVENTUR v United States mii APPARATUS FOR LAPPIN G DIES Giles P. Hafer, Kenmore City, N. Y., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application May 27, 1955, Serial No. 511,638

2 Claims. (CI. 51-97) This invention relates to apparatus for lapping dies particularly carbide wire drawing dies.

A common practice in lapping carbide diesis to use an abrasive paste so thick that it does not run readily and when placed in the die opening being lapped, works its way into the lapping surfaces very slowly. The speed of the lapping process could be increased extensively if it were possible to use a thinner free flowing mixture of abrasive material but this is impracticable with conventional lapping machines since it is impossible to prevent thin abrasive material from flowing out of the die and into bearings and other parts of the machine.

An object of the present invention is the solutions to these problems in an efficient and highly practical apparatus for lapping dies.

With this and other objects in view, the invention comprises an apparatus for lapping dies including a lapping spindle rotatable about its axis, a holder for a die rotatable about its axis with means to supply a fluid abrasive to the die in the holder and a reservoir positioned to receive the excess fluid abrasive and prevent it from damaging other parts of the apparatus.

In the present embodiment of the invention, a plurality of lapping units have a main drive shaft with individual driving means for the lapping spindles in the units and the die holders thereof. Also a cam shaft driven by the drive shaft actuates means to raise the lapping spindles at predetermined intervals to free the abrasive to flow in each die toward its reservoir. Although all of the pivotally supported holders for the dies of the units are connected to one reciprocable slide to bring about their rocking movements relative to their respective lapping spindles, each die holder is provided with individual means for adjusting the amplitude of its rocking motion so that dies requiring apertures of different contours may be lapped simultaneously.

Other objects and advantages will be apparent from the following detailed description when considered in conjunction with the accompanying drawings, wherein:

Fig. 1 is a front elevational view of the apparatus showing the compact relationship of the plurality of lapping units, portions of the control means for the apparatus being omitted from this figure;

Fig. 2 is a vertical sectional view of the apparatus disclosing the main drive shaft and the driving means for one of the units;

Fig. 3 is an enlarged fragmentary elevational view of a portion of one of the units showing the die holder and reservoir in cross-section;

Fig. 4 is a top plan view of the unit at the extreme right of Fig. 1 illustrating the driving means therefor and the additional driving means for the actuator;

Fig. 5 is a fragmentary vertical sectional view taken substantially along the line 55 of Fig. 4;

Fig. 6 is a fragmentary sectional view of the actuator operating means, and

Fig. 7 is a fragmentary sectional view taken along the line 7-7 of Fig. 6.

Referring now to the drawings, Fig. 1 illustrates a I frame 10 mounted on a base 11 and including lateral members 12, 13, 14 and 15 for receiving their respective parts of six units identified by reference numerals 16, 17, 18, 19, 20 and 21. The units 16 to 21 inclusive are substantially identical in structure, the only difference lying possibly in the die holders to accommodate dies of different sizes and the possible contours of the Therefore, a description of one of the units will apply equally well to all otherunits. Attention is directed to Figs. 2 and 4 which illustrate a j lapping spindles.

main drive shaft 24 journalled in suitable bearings 25 (only one of which is shown). The drive shaft 24 may 'be driven continuously from a power means (not shown) through. a belt 26 extending around a pulley 27 fixed to the shaft 24.. A'pul1ey28 mounted on the drive shaft 24 is operatively connected to a shaft 29 by a belt 30 extending around a pulley 31 mounted on the shaft 29. The belt 30 extends over grooved idler pulleys 33 (Figs. 2 and 5) supported for rotation on a shaft 34 carried in a hollow arm 35. The shaft 29,

like all others of the units, is rotatably journalled in apertures 38 and 39 of the lateral portions 12 and 13 of the frame and the pulley 31, fixed to the shaft 29,

rests upon yoke 40 to thereby support the shaft 29 with bits chuck 41 and lapping spindle 42. The yoke 40,

shown in Fig. 2, is fixedly mounted on a rod 44 mounted for vertical movement in apertures 46 and 47 in members 12 and 13. The lower end of the rod 44 has a head 48 integral therewith to rest upon a cam 49 which is mounted upon a shaft 50. There is a cam 49 for each unit which is mounted on the shaft 50 and as theshaft is rotated, the cam of each unit will move its rod 44 to move its spindle 42 free of its respective die.

The shaft 50 (Figs. 2 and 4) derives power from the main drive shaft 24 through a pinion 52 on the shaft 24, a gear 53 on a shaft 54 and a belt and pulley connection 55 between shafts 50 and 54. The ratio of the pinion 52 and gear 53 determines the ratio between the elevating means and the rotating means for each lapping spindle 42.

Each unit, of the group 16 to 21 inclusive, has a support 60 with parallel bearing members 61 and 62 to support a spindle 63 having a threaded aperture in the upper end thereof. A pulley 66 mounted on the spindle 1 63 is connected by a belt 67 to a pulley 68 (Figs. 2

and 4) mounted on the drive shaft 24. The belt 67 from reaching the spindle or any of the other moving parts. A threaded pin 76 mounted in the threaded aperture in the upper end of the spindle 63 is carried by or integral with a die holder 77. The die holder 77 may be one of a plurality of die holders of varying contour-s depending upon the size and contours of the dies to be lapped. However, the die holders, although differing in size, are substantially identical in general contour in that they are cup-shaped to receive their respective dies 80 and are provided with grooves or passageways 81 extending radially from the center of the bottom portion of the die holder for communication with the aperture 82 of the die and to permit an abrasive material to flow from the die opening through the passageways and into the reservoir. The die holder 77 is externally threaded to receive an internally threaded cap 84 open at its center to receive abrasive material but adapted to hold the dies singly in the holder. The bottom surface of the die holder 77 has downwardly extending baflles 85 which, in a sense, overlap and interengage the areas of the bafiies 73 of the reservoir to eliminate any possi- Patented A r; 30, 1-957 s r 2,790,278 a rv r 3 bility of the abrasive material passing trom'theresrvoir or the die holder to the moving parts of the apparatus.

Each support has a longitudinal aperture 87 with parallel fins 88 to receive an adjusting element or pivot pin 89,;movable in 'verticallyextending elongated-apertures in a slide 92. The element 89 in each instance has a threaded aperture 90 through which an adjusting screw 91 extends. The adjusting screw is held against longitudinaimovement by suitable supporting means at each end'thereof and during rotation of the screw, the location of the element 89 in each instance varies the rocking motion of each support 60 about its pivot 93 (Fig. 2). The pivots are mounted in apertures in the lateral member 14. It will be apparent that if the actuator 92 moves a given distance between knownxlimits, the closer the element 89 for :each unit approaches its pivot 93, the greater will be'the swinging movement of each die, holder. The actuator 92 issupported in suitableguides in the members 14 and 15 and is connected pivotally at 95 to an arm 96 of an eccentric 97. The eccentric 97 is mounted on a shaft 98 journalled in suitable bearings of-arms 99 and has a pulley 100 mounted on the end thereof. The pulley 100 is connected by a belt 101 to a pulley 102 on shaft 54 thereby receiving driving connection from the main drive shaft 24.

The idler pulleys 33 of the arm 35 are under the control of a rod 106, having a handle 107 and a threaded'ly, adjustable connection 108 with a pivot 109. The pivot-109 is carried by the arm 35 and adapts the rod 106 to move the arm from a driving positionshown to an idling position where the belt 30 may be made sufiiciently loose on the pulleys 28 and 31 to remove its driving connection therefrom. The arm' 35 pivots on a support 110 and the rod 106 may be held in either of the aforementioned positions by suitable means such as a pin 111 associated with suitableretaining means 112. In' a similar manner a control rod 114 with a pin 115 and a notched retaining element 116 may be moved into either its driving or idling position. The threaded connection of the rod 114 at 118 with a pivot 119 of the arm 70 provides adjustment of the idler pulleys 71 between a sufiiciently tight driving position shown and a loose idling or unoperating position.

Considering now the operation of the apparatus, the abrasive material may be deposited in the dies in each unit in any suitable manner such as through a feeding means 120 (Fig. 3). During setting up of the apparatus, the lapping spindles 42 are in their upper positions making possible the removal of lapped dies and the mounting of new dies to be lapped in their respective die holders 77. The units may be brought into operation singly by actuating their rods 106 and 114 and in the same manner the units may be rendered unoperated singly or selectively without disturbing the operation of the other units. During continuous rotation of the shaft 24, the actuator moving mean-s, deriving its power through belt 101, operates continuously with the elevating means including the camshaft 50, deriving its power through the belt 55. However, the individual units depend upon the actuation of their rods 106 and 114 to bring about driving of their lapping spindles 42 surfaces of the die apertures.

.10 that in the present instance the abrasive material is in l and their die holders 77. The size and contours of the bell-shapedv openings 82 in the dies 80 will determine the degree of adjustment necessary for the rocking movements of the die holders. This may be brought about readily through adjustment of the screws 91. As the apparatus continues its operation bringing about varied swinging motions of the dies being lapped, the abrasive material may flow between the lapping spindles and the This is due to the fact the form of a fluid, deposited periodically on the dies adjacent the die openings. Furthermore, periodically, the spindle in each unit is raised to allow the abrasive material to flow .freely to increase the efiiciency of the lapping operation while the passageways 81 direct the excess abrasive material out of the die holder in each instance and into its reservoir '72.

It is to be understood that the above described arrang'ementsare simply illustrative of the application of the principles of the invention. Numerous other arrangementsmay be readily devised by those skilled in the art which will embody the principles of the inven- =thereby, the holder having passageways extending from adjacent'positions in communication with the die aperture radially through the holder, means to rotate the holder, means to supply a fluid abrasive to the die in the holder, a reservoir for receiving the fluid abrasive,

. :and means to raise thespindleat predetermined intervals to free the abrasive to flow through the die aperture whereitwill be forced by centrifugal force through the radial passageways into the reservoir.

2. In an apparatus for lapping dies, a lapping spindle rotatable about its axis, means to rotate the spindle, a

carriage mounted on a pivot disposed at right angles to the axis of the spindle, a holder for the die supported by the carriage, rotatable about its axis and having a central aperture disposed in alignment with a central aperture of the die to receive the spindle for lapping of the die aperture therewith, the die holder having passageways in communication with the die aperture and extending radially through the holder, means to rotate the holder, means to supply a fluid abrasive to the die in the die holder, a reservoir for receiving the fluidabrasive from the die holder mounted on the carriage, and means to raise the spindle at predetermined intervals to free the fluid abrasive to flow through the die aperture where it will be caused to flow radially through the passageways and into the reservoir by centrifugal force.

References Cited in the file of this patent UNITED STATES PATENTS 819,628 Alton May 1, 1906 1,925,751 .Diifen-derfer Sept. 5, 1933 2,292,550 Simons Aug. 11, 1942 2,350,023 Perrier May 30, 1944 

